Air Filter for CNC with ATC

[Brad Shipton]

So I finally found out why I was having problem tripping my spindle when I would use air to clean off my table. My air compressor is located far from my CNC. On Monday my spindle tripped just as it was grabbing a tool and it would not reach pressure. The air pressure at my compressor was fine, but I found that my one filter had clogged to the point that the pressure had dropped too low on the outflow side. I replaced the filter and all is running again. Between the compressor and my spindle I have a desiccant filter and Milton coalescing filter. I added an auto drain to my air compressor about 8months ago, and that made a huge difference to removing water in my line. Looking into things a bit closer now it turns out the desiccant my filter uses is very corrosive to the steel housing, so I need to replace it to avoid rust particulates clogging the filter downstream. I know commercial shops use freeze dryers and I likely should bite the bullet and put one in. I was trying to avoid spending another $1,500 (no harbor freight option here), but now that I have to replace that desiccant filter I am thinking it might be time to stop the slow bleeding of funds. My question (finally) is what are most using? I likely put 300 - 500hrs on my machine in 2years.

Thanks

[Brian Lamb]

Search refrigerated air dryer on ebay, you don't need huge CFM, so they aren't that expensive, probably can find one under $500. Check your local Craig's List and Offerup too... they are pretty common and I see them real cheap on occasion. Living in Arizona, it's not a huge issue for me, but we had several back when I owned a machine shop and we had much larger compressed air needs. The big one was nothing more than a radiator coil with a fan over it, but it wasn't 100% effective, so we added a refrigerated version for the Coordinate Measuring Machine (CMM) that ran with air bearings and had to have clean and dry air.

[Gary Campbell]

Brad...
You might want to reconsider the HF option. I know a few guys with non commercial shops, and even 1 that does commercial work that have used them with success. And the price is right

[Brad Shipton]

I noticed a few good reviews of the Harbor freight model, and I see they ship to Canada now that I look closer. They ship via FedEx, so I will have to see if it makes sense. $1500 was CAD, which is about $1125 USD. It seems the refrigerated solution is the way I should go. I will need one for about 15cfm, which is small. It would be nice to have the capacity for spraying too.

Thanks

[Mark Bolton]

We have an aftercooler on the compressorand auto tank drain followed by refrigerated dryer and a high dollar hakinson coalescing filter and then have a filter at the drop at the cnc just to catch anything from the steel lines. The shop was plumbed in black pipe and likely had a bunch of scale so was worried.

Our dryer was around 1100 as I recall. It's a good investment all around in my opinion and more so if your spraying a lot of finish.

[Brad Shipton]

Thanks Mark. I was curious what you are using. I ran copper for all my air lines. I do not spray a lot, but now that I plumbed the main compressor to the booth I might as well do as best I can. Most of the dryers I have looked at so far seem to start at sizes for a 5hp compressor.

[Bill George]

Black pipe is the commercial standard for compressed air lines. Its not suppose to have air with water. Copper is a good choice and they make a grade of plastic pipe rated for compressed air, Not PVC. It was banned by OSHA as it fractures and becomes shrapnel. I have a refrigerated air dryer I took out as the automatic drain was leaking and I got tired of messing with it, and never used since I sold my CNC plasma cutter. I would give it away if someone is close by.

[Mark Bolton]

It seems you tend to lean towards higher end stuff with regards to tooling but I too had heard and read some decent reviews of the harbor freight models. I just for my own goofy reasons refuse to shop there. We have a local industrial compressor rep about 45 minutes away and I wanted support for the compressor so I just went with them for all the components. They were cheaper on the compressor but I likely could have saved a little shopping around on the dryer and the coalescing filter. I spoke with a few shops that were running nothing. Just compressor and maybe a simple filter regulator on the drop to the cnc. I wanted to feed the spindle with the cleanest and dryest air I could because it gets real humid here.

My shop use to be the old town firestateion and was already plumbed with black pipe to feed the air brakes on the trucks so we were lucky there but that was an additional reason for the dry air creating rust in the lines.

[Brad Shipton]

In Canada we have something similar to Harbor Freight. It is called Princess Auto. They are not nearly as big, but they have a similar business plan. I try to avoid shopping there, but I do every once in a while. They have an awesome return policy and no sale is ever final to them. I exchanged an un-used electric motor 1.5yr after I had bought it. No receipt and they did not carry it any longer. They exchanged without any discussion. My brother had a similar story. He had overloaded a hoist he bought there, and before he could finish his story they were loading him up with a replacement. I would buy one of these from them, but they do not carry any. I am getting a bit tired of Fedex and UPS at the border. I might talk to the industrial supplier again.

[Mike Heidrick]

1. Auto tank drain
2. Regulator and watwr seperater
3. 50' copper after cooler with drip legs
4. Harbor Freight refridgerated dryer
5. Maxline 3/4 line to highest spot in run
6. Continious fall away fron compressor to 5 drops and two ceiling runs per 1/2 of shop
7. Each drop has regulator and water seperator and drip leg
8. Two filters at plasma machine, one at the big mill and one at glue up rack.

1/2 of shop has 80 gal ingersol and the other 1/2 of shop has 60 gal sanborn that will be replaced by 60gal puma. Each 1/2 has the setup above. Total line is about 400' of maxline. With the above drying ideas I dont have any discernable moisture in any of the lines.

[Mark Bolton]

Why with a refrigerated dryer, an aftercooler, and the effort of pitched lines, would you feel the need to put water separators and drip legs at every drop? That seems like belt and suspenders on high dose steroids?

Our aftercooler and tank drain takes it to 80%. Hakinson refrigerated dryer takes it to zero. Coalescing filter takes care of oil. And the only reason we filter at the cnc is because of existing black pipe lines and scale/rust.

If we had run pex, copper, plastic, aluminum, I'd have nothing but a reg and no drip at every drop. Out air beyond the coalescing is likely close to hospital air.

[Brad Shipton]

Thanks Mike. I had looked thru your shop build when you mentioned how well your DC was working to find its size. I did not see all of that description.

What are most doing as far as an aftercooler is concerned on your Air Compressor? I am looking at a Refrigerated unit that has a built in after cooler. I see quite a few doing home built after coolers, but many do not seem to understand the difference between the air pressure between a car and a compressor.

[Mark Bolton]

Our after cooler is factory installed on the compressor but is just a small radiator behind the compressor head and head pulley which has a fan built into the pully drawing air across the cooler and then across the head. The piping from the low point of the cooler is plumbed into the low point after the pressure switch. So when the compressor shuts down it bleeds all the downstream air between the check valve and the head.

I would honestly think with a tank drain and refrigerated dryer you'd be in good shape unless your compressor is running non stop. Most dryers have far more capacity than the compressor in a light use situation.

[Gary Campbell]

"

I would honestly think with a tank drain and refrigerated dryer you'd be in good shape unless your compressor is running non stop. Most dryers have far more capacity than the compressor in a light use situation."

Double thumbs up +1

[Brad Shipton]

Now that I think about the amount my compressor runs typically that makes sense. I think I will stick with one of the common ones most use.